1. Field of the Invention
This invention relates to breathing apparatus and more particularly, but not exclusively, is concerned with breathing apparatus for use by the fire fighting services.
2. Description of the Prior Art
Breathing apparatus are known comprising one or more cylindrical containers for storing breathable gas and a harness for securing the cylinder(s) to the back of the user of the apparatus. However the cylinders tend to be long and heavy and are rather unwieldy to carry because the centre of gravity is high up on the wearer""s back.
It is an object of the present invention to provide a breathing apparatus which can be more readily carried by the wearer.
According to the present invention there is provided a breathing apparatus comprising:
(i) a substantially spherical container for holding breathable gas under pressure, and
(ii) a harness to which the container is attached for securing the container to the user.
By making use of a substantially spherical container, it is possible to arrange for the centre of gravity to be lower down the back of the wearer to assist in the comfort and manoeuvrability of the wearer when carrying the apparatus.
The apparatus may comprise more than one of said substantially spherical containers connected together by means of a suitable manifold. In this case it is preferred that the containers are charged simultaneously and discharged simultaneously. By providing a variable number of containers, it is possible to accommodate variable breathing consumption rates and variable durations of use in order to render the apparatus suitable for a wide variety of operational circumstances.
In accordance with one embodiment of the invention, a single spherical container is provided. This embodiment is suitable for use for short periods of time such as when escaping from a hostile environment or when carrying out quick and/or simple tasks. In this case, the harness may be in the form of a waist belt or waist coat for fastening around the user and to which the container is secured. If desired, the waist belt may be in the form of a fire-fighter""s DIN standard safety belt with the container secured thereto by suitable xe2x80x9csnap-onxe2x80x9d attachments. Alternatively, the harness may be in the form of a bandolier arranged to extend diagonally around the body of the user.
Similar harnesses may be used in the case where the apparatus includes two of said containers.
However, when the apparatus includes two (or more) containers, it is preferred for the harness to be a full harness including both a waist belt and also shoulder straps for looping around the shoulders of the wearer. In this case, it is particularly preferred for the harness to include a waist plate providing lumbar support as a consequence of having a back portion for engaging the back of the wearer and side portions, at each end of the back portion, having lips at their upper edges for seating on the hips of the wearer. Optionally, the harness additionally includes a spinal support plate for engaging the spine of the wearer. The spinal support plate is preferably pivotable in a vertical plane generally parallel to the back of the wearer and/or flexible in a direction perpendicular to that plane. It also may be height adjustable.
It is particularly preferred for the breathing apparatus to include a protective casing for the container(s) formed of lightweight non-flammable antistatic material. In the case where a single container only is provided, this may be in the form of a bag accommodating the container and affixed to the harness. In the case where the breathing apparatus includes more than one container, then the casing is preferably a relatively rigid container. Where two containers are provided, these are preferably located side-by-side within a single casing and, in an embodiment, the casing may include sufficient space to accommodate a third container above the first and second containers so that the containers are located at the apices of a triangle. In this way, the user can include two or three containers as desired depending on the purpose of use of the apparatus.
In the case where the apparatus includes four containers, these are preferably located in pairs with one pair above the other and each pair in its own separate casing with the casings interlocking together to provide additional stability and security.
In the case where more than one container is used, quick connections are preferably provided to enable them to be connected to the necessary manifold. Generally, in each case, the casing includes two openings only namely a high pressure inlet leading to the container (or, in the case where more than one container is present, to a manifold connecting the containers together) for charging the container(s) with gas and an outlet linked to the container or manifold as the case may be via a pressure reducer so that gas at medium pressure can be fed to the demand valve of the apparatus to enable the user to breathe the gas. If desired the casing may be provided with heat-insulation and with a radiation-reflective surface.
By totally enclosing the container(s) in a casing, there is much less risk of the apparatus snagging on any protrusions or trailing wires in the vicinity and the container(s) and pressure reducer, manifold and the like are less vulnerable to accidental damage. Moreover, cleaning and particularly decontamination of the apparatus after use is greatly simplified. Generally, the containers only need to be removed from the casing when it is needed to carry out periodic pressure testing.
It is particularly preferred for the container(s) to be formed from a composite material such as, for example, resin impregnated graphite fibres in which case they can be produced by a filament winding technique. Such composite containers are preferred because of their light weight. If desired, however, containers formed from, for example, steel or aluminium may be used.
The containers may contain any breathable gas but generally this will be compressed breathing air.